Energy-Transfer Mechanism and Typical Operating Characteristics for the Thermal rf Plasma Generator

Abstract

Operating characteristics of an atmospheric-pressure, rf plasma torch and of its associated 30-kW power oscillator are inferred from available instrumentation and calorimetric heat balance measurements with various working fluids in torches of two diameters. The governing equations for the arc, neglecting convection, are derived and solved analytically for the crude channel-model approximation. Material functions for argon and nitrogen are then used to predict operating characteristics for these fluids. Fair agreement indicates that at least some of the essential physical phenomena of the discharge have been resolved. The analysis serves to explain much of the ``art of operation'' with special emphasis on the concepts of coupling and impedance matching.